Projection Device and Method for Controlling Projection Device

The present application is based on, and claims priority from JP Application Serial Number 2025-014792, filed January 31, 2025, the disclosure of which is hereby incorporated by reference herein in its entirety.

The present disclosure relates to a projection device and a method for controlling a projection device.

According to the related art, as disclosed in JP-A-2010-109585, there is known an device that cancels processing of correcting a keystone distortion and projects a guide pattern so that the user can install the device horizontally, when the start of movement is detected.

JP-A-2010-109585 is an example of the related art.

However, with the above-described device, it is difficult for the user to grasp the state of the keystone distortion correction processing simply by viewing the guide pattern, and this may be inconvenient.

According to an aspect of the present disclosure, a projection device includes: a projector configured to project an image on a projection surface; a housing configured to accommodate at least a part of the projector; a sensor configured to detect a movement or stop of the housing; and one or a plurality of processors, and the one or plurality of processors cause the projector to project a notification image notifying that processing of geometric correction on the image is not finished, when it is determined that the housing is moving, based on a result of detection by the sensor.

According to another aspect of the present disclosure, a method for controlling a projection device including a projector configured to project an image on a projection surface, a housing configured to accommodate at least a part of the projector, a sensor configured to detect a movement or stop of the housing, and one or a plurality of processors, is provided, and the method includes causing, by the one or plurality of processors, the projector to project a notification image notifying that processing of geometric correction on the image is not finished, when it is determined that the housing is moving, based on a result of detection by the sensor.

Hereinafter, embodiments will be described with reference to the drawings. Note that directions in the drawings are described, using a three-dimensional coordinate system. For the sake of convenience of description, a positive direction on a Z axis is referred to as an upward direction or simply as above, a negative direction thereon is referred to as a downward direction or simply as below, a positive direction on an X axis is referred to as a rightward direction or simply as right, a negative direction thereon is referred to as a leftward direction or simply as left, a positive direction on a Y axis is referred to as a rearward direction or simply as rear, and a negative direction thereon is referred to as a forward direction or simply as front.

1 2 FIGS.and 1 10 11 15 20 25 24 27 30 As shown in, a projection deviceincludes a housing, an operation panel, a memory, a controller, a communicator, a camera, a sensor, and a projector.

10 15 20 25 27 30 11 10 The housingaccommodates the memory, the controller, the communicator, and the sensor, and accommodates at least a part of the projector. The operation panelis installed at an upper part of the housing.

30 1 15 20 As will be described later, the projectorof the projection devicecan project image data and the like stored in the memoryonto a projection surface SC on the rear side as a projection image PG under the control of the controller. The projection surface SC is a screen, a wall, or the like. The projection is also referred to as image/video projection, video projection, or image projection.

20 1 20 20 20 The controllercomprehensively controls the elements of the projection device. The controllerincludes one or a plurality of CPUs (central processing units), a UART (universal asynchronous receiver-transmitter) that manages inputs and outputs, and an FPGA (field-programmable gate array) and a PLD (programmable logic device), which are logic circuits, and the like. The controller 20 is also referred to as a processor. The CPU of the controllermay be particularly referred to as a processor. The controllercan include one processor or a plurality of processors corresponding to functions to be processed, respectively.

15 15 The memoryincludes a flash ROM (read-only memory) and an HDD (hard disk drive), which are rewritable nonvolatile memories, and a RAM (random-access memory), which is a volatile memory. The nonvolatile memory of the memorymay include an SSD (solid-state drive).

20 15 The CPU of the controllerreads a program P such as firmware stored in the nonvolatile memory of the memoryand executes the program P, using the volatile memory as a work area.

15 15 15 Various types of image data are stored in the memory. Hereinafter, the image data is also simply referred to as an image. The memorystores a notification image A, which is notification image data. As will be described later, the memoryalso stores a content image D, which is content image data, a projection image PG, which is projection image data, a correction image C, which is correction image data, and the like.

25 The communicatorincludes a circuit that can communicate wirelessly or via a wire. The communicator 25 includes an antenna when performing wireless communication, and includes a connector when performing communication via a wire.

25 50 50 25 15 The communicatorcan communicate with an external device, which is an image supply device such as a computer or a DVD player. The communicator 25 can receive the content image D from the external device. The content image D received by the communicatoris stored in the memory.

1 11 11 13 13 11 1 11 The projection deviceincludes the operation panel. The operation panelincludes a plurality of input buttons. The user operates the input buttonsof the operation panelto configure various settings and give various instructions of the projection device. The operation panelmay be a touch panel display including an inputter and an outputter.

11 20 The operation panelcan accept an operation of setting the type of language by the user. The controllercan change the content of the character string of each of a first message AM included in the notification image A and a second message CM included in the correction image C, which will be described later, according to the type of language set by the operation of the user.

27 10 27 10 27 27 20 27 10 The sensoris fixed to the housing. The sensoroutputs a detection value corresponding to the movement of the housing. As the sensor, for example, a velocity sensor, an angular velocity sensor, an acceleration sensor, an inclination sensor, or the like can be used. The sensoris, for example, a gyro sensor. The controllercan acquire a detection value from the sensorand detect the movement or stop of the housing.

20 10 27 20 10 27 The controllerincludes a timer (not illustrated), and can also calculate the speed at which the housingmoves, based on the detection value of the sensoracquired at predetermined time intervals. For example, the controllercan calculate a first speed at which the housingmoves, a second speed faster than the first speed, and the like, using the sensor.

20 24 10 27 Also, the controllermay pick up, with the camera, the projection image PG, the notification image A, or the like, which will be described later, projected onto the projection surface SC, at predetermined time intervals, and determine whether the housingis moving or stopped, based on whether there is a change in the image. In this case, the sensormay not be used.

20 10 10 The controllermay detect whether there is a change in the distance between the housingand the projection surface SC, using a time-of-flight (TOF) sensor, and determine whether the housingis moving or stopped.

24 24 The cameraincludes an image sensor such as a charge-coupled device (CCD). The cameracan pick up the projection image PG and the like projected on the projection surface SC.

20 24 1 1 1 1 1 The controllercan acquire a picked-up image picked up by the cameraand detect the inclination of the projection devicein relation to the projection surface SC, the posture of the projection device, the image shape of the projection image PG, the distance between the projection deviceand the projection surface SC, the facing angle of the projection deviceto the projection surface SC, the projection surface shape of the projection surface SC, and the like. The facing angle is the angle between the optical axis of the light projected by the projection deviceand the projection surface SC.

30 30 31 33 35 37 3 FIG. Next, the projectorwill be described in detail with reference to. The projectorincludes a light source, a liquid crystal light valve, a light valve driver, and a projection lens.

31 31 31 31 33 20 a b The light sourceincludes a light emitter, a reflector, an optical integration system (not shown), and a color separation system (not shown). The light sourceemits light to the liquid crystal light valveunder the control of the controller.

31 31 31 31 a a b The light emitteris a xenon lamp, an ultra-high-pressure mercury lamp, an LED, a laser light source, or the like. The reflector 31b reduces variations in the direction of emission of the light emitted by the light emitter. The optical integration system reduces variations in the luminance distribution of the light emitted from the light source. The color separation system separates the light having passed through the reflectorinto red, green, and blue color light components.

33 31 33 The liquid crystal light valvemodulates the light emitted from the light source. By modulating the light, the liquid crystal light valvegenerates the projection image PG or the like, which is an image to be projected.

33 33 33 33 33 33 a p p The liquid crystal light valveis formed of a liquid crystal panel made up of a pair of transparent substrates with liquid crystal enclosed therebetween. A rectangular pixel areaincluding a plurality of pixelsarranged in the form of a matrix is formed in the liquid crystal light valve. In the liquid crystal light valve, a drive voltage is applied to each pixel.

33 33 33 33 The liquid crystal light valveincludes three liquid crystal light valves, that is, a red-light liquid crystal light valveR, a green-light liquid crystal light valveG, and a blue-light liquid crystal light valveB.

33 33 33 A red color light component separated by the color separation system becomes incident on the red-light liquid crystal light valveR. A green color light component separated by the color separation system becomes incident on the green-light liquid crystal light valveG. A blue color light component separated by the color separation system becomes incident on the blue-light liquid crystal light valveB.

35 20 33 20 35 33 33 p p p The light valve driveris coupled to the controllerand applies a drive voltage to each pixel, based on image data corresponding to the projection image PG or the like, under the control of the controller. When the light valve driverapplies a drive voltage to each pixel, each pixelis set to a light transmittance based on the image data. The drive voltage is supplied by a power supply (not shown).

31 33 33 33 33 a The light emitted from the light sourceis transmitted through the pixel areaand thus modulated. The red-light liquid crystal light valveR, the green-light liquid crystal light valveG, and the blue-light liquid crystal light valveB form color component images for the respective color lights.

33 The element that modulates light may not be the liquid crystal light valve. For example, a transmissive liquid crystal panel, a reflective liquid crystal panel, a digital micromirror device or the like may be used.

37 33 37 The projection lenscombines the color component images formed by the liquid crystal light valvesand projects the combined image in an enlarged manner. The projection lensprojects the projection image PG or the like onto the projection surface SC. The projection image PG or the like projected on the projection surface SC is an image formed by combining the color component images.

1 15 20 15 30 Hereinafter, it is assumed that images to be projected by the projection deviceare stored in the memory, each as a single image, or as a combination of a plurality of images. Also, the execution of a series of processes in which the controllerreads one image from the memoryand projects the image onto the projection surface SC by the projectoras described above will be omitted.

4 FIG. 20 101 As shown in, the controllerstarts the processing and projects, for example, an image such as the projection image PG based on the content image D onto the projection surface SC in (S).

10 1 At this time, depending on the relative positional relationship between the housingof the projection deviceand the projection surface SC, a geometric distortion may occur in the projection image PG projected on the projection surface SC. For example, a so-called keystone distortion may occur, in which the projected projection image PG, which originally should be rectangular, is trapezoidal. The keystone distortion is an example of the geometric distortion.

10 5 FIG. For example, it is assumed that the housingis installed in a posture inclined downward at a predetermined angle with respect to the projection surface SC. In this case, as shown in, the contour of the projection image PG projected on the projection surface SC has a keystone distortion such that the contour is in a trapezoidal shape with a short upper side and a long lower side.

10 1 The user may move the housingof the projection devicein relation to the projection surface SC in order to correct the keystone distortion of the projection image PG.

20 10 27 102 20 27 10 103 The controllerdetects the movement state of the housingby the sensor(S). The controlleracquires the detection value from the sensorand determines whether the housingis moving in (S).

20 10 103 20 104 1 5 FIG. When the controllerdetermines that the housingis moving, due to the detection value being equal to or greater than a predetermined value (YES in S), the controllerprojects the notification image A as illustrated in(S). The notification image A is also an image for the projection deviceto notify the user.

20 15 The controllermay combine the projection image PG and the notification image A in the memoryand project the combined image.

20 20 For example, the controllercan superimpose the notification image A on the projection image PG subjected to the transmission processing, thus combine these images together, and project the combined image. At this time, the controllermay perform reduction processing for reducing the visibility of the projection image PG. Examples of the reduction processing include pixelization processing, luminance reduction processing, tone reduction processing, and the like. In the following description, reducing the visibility is also referred to as decreasing the visibility.

20 In this way, the controllercan perform the reduction processing of reducing the visibility on the projection image PG, which is a first image, to obtain a second image, and superimpose the notification image A on the second image.

20 15 The controllermay switch the target to be read from the memoryto the notification image A and project only the notification image A.

5 FIG. 20 As shown in, similarly to the projection image PG, the notification image A, too, is projected in a distorted trapezoidal shape on the projection surface SC. The projection of the notification image A is also preprocessing for correction, described later, on the projection image PG by the controller.

5 FIG. As shown in, the notification image A projected on the projection surface SC includes a first message AM, which is a character string, a first guide pattern AG, which is a rectangular frame, and a first background image AB. Preferably, a single color is used for the first message AM and the first guide pattern AG.

The notification image A includes "correction in progress" of the first message AM, which is a character string notifying that the geometric correction processing is not finished.

15 20 The first message AM, the first guide pattern AG, and the first background image AB may be stored in the memoryas individual images and combined together as the notification image A by the controller.

1 The first message AM is preferably located at the center of the notification image A. The first guide pattern AG is preferably a rectangular frame including an area of a maximum range that can be projected by the projection device.

1 4 In the first background image AB, the gradation becomes darker and the tint is blurred toward the center of the notification image A, and the gradation becomes lighter and the tint is blurred toward four corners ABto ABof the first background image AB.

1 4 1 2 3 4 1 4 The four corners ABto ABare a lower left corner AB, an upper left corner AB, an upper right corner AB, and a lower right corner AB. The four corners ABto ABare also the four corners of the notification image A and are also the four corners of the first guide pattern AG.

The gradation may become lighter and the tint may be blurred toward the four sides of the first guide pattern AG representing a rectangle.

In this way, the brightness of the first background image AB of the notification image A increases continuously or in stages in the direction toward the periphery. In this case, the user is less likely to feel something is wrong than when the vicinity of the periphery of the first background image AB has an edge or the like.

The gradation of the first background image AB is, for example, of a color such as red, green, or blue, and a single color is preferably used. The gradation may be of a color using gray tone including white. The first background image AB may be white without using gradation.

The gradation or the like of a second background image CB of the correction image C, described later, can be similar to that of the first background image AB described above.

10 10 The first guide pattern AG of the notification image A, too, which should originally be projected as a rectangular frame, is projected in a distorted trapezoidal shape on the projection surface SC. When correcting the inclination of the housing, the user can use the first guide pattern AG of the notification image A projected on the projection surface SC as a guide. The user can move the housingby attempting to make the first guide pattern AG have the original rectangular shape while viewing the first guide pattern AG.

1 In this way, the first message AM at the center of the notification image A has a clear contrast difference from the first background image AB having a dark gradation, and is easily visually recognized by the user. When the first background image AB is white, the first message AM may be black or colored. With the first message AM, the user can recognize that the projection deviceis in the state of "correction in progress" on the keystone distortion.

20 10 20 20 10 As will be described later, when the controllerdetermines that the housingis moving, the controllerdoes not correct the keystone distortion. The controllerstarts the correction after the housingstops.

20 10 27 20 30 In this way, when the controllerdetermines that the housingis moving, based on the result of detection by the sensor, the controllercauses the projectorto project the notification image A notifying that the processing of the geometric correction on the projection image PG or the like is not finished.

Even at the preprocessing stage for the correction, described later, the user can visually recognize the projection of the notification image A and grasp that the state of the correction processing such as the geometric correction on the projection image PG is "correction in progress", which means that the processing is not finished, and this is convenient.

20 10 27 103 20 105 6 FIG. Meanwhile, when the controllerdetermines that the housingis not moving and is stopped, due to the detection value from the sensorbeing less than the predetermined value or the like (NO in S), the controllerprojects the correction image C for correcting the keystone distortion of the projection image PG as shown in(S).

20 15 The controllermay combine the projection image PG and the correction image C together in the memoryand project the combined image, as in the case of the notification image A described above.

20 20 For example, the controllercan superimpose the correction image C on the projection image PG subjected to the transmission processing, thus combine these images together, and project the combined image. At this time, the controllermay perform the reduction processing for reducing the visibility of the projection image PG. As described above, examples of the reduction processing include pixelization processing, luminance reduction processing, tone reduction processing, and the like.

20 In this way, the controllercan perform the reduction process of reducing the visibility on the projection image PG, which is a first image, to obtain a second image, and superimpose the correction image C on the second image.

20 The correction on the correction image C by the controlleris also a correction on the projection image PG to be superimposed.

20 15 The controllermay switch the target to be read from the memoryto the correction image C and project only the correction image C.

20 10 27 As described above, the controllercan calculate the first speed at which the housingmoves, the second speed faster than the first speed, and the like, based on the result of detection by the sensor.

20 As described above, the controllercan perform the following processing when performing the reduction processing of reducing the visibility of the projection image PG, which is the first image, so as to obtain the second image.

20 10 27 That is, the controllercan perform the reduction processing such that the visibility of the projection image PG when the speed is the first speed becomes lower than the visibility of the projection image PG when the speed is the second speed, based on the result of calculation of the speed of the housingusing the sensor.

20 10 10 The controllerstrengthens the reduction processing as the speed at which the housingmoves becomes slower, and weakens the reduction processing as the speed at which the housingmoves becomes faster.

20 When the speed is the first speed, at which it is relatively easy for the image to catch the user's eye, the controllercan make the projection image PG changed by the correction less perceptible, and therefore can reduce the user's feeling that something is wrong.

20 20 Meanwhile, when the speed is the second speed, at which it is relatively difficult for the image to catch the user's eye, the controllercan make it difficult for the user to feel that something is wrong even if the projection image PG changed by the correction is easily perceptible. When the speed is the second speed, the controllermay stop the reduction processing.

10 10 10 20 106 It is difficult for the user to correct the keystone distortion of the projection image PG by changing the posture of the housing. Therefore, when the user stops changing the posture of the housingand the housingstops, the controllerperforms the correction (S).

20 20 The projection of the correction image C described above can also be said to be the processing of starting the correction by the controller. Hereinafter, the correction processing by the controllerwill be described in detail.

6 FIG. 20 As shown in, when correcting the keystone distortion, the controllerprojects the correction image C on the projection surface SC.

The correction image C corresponds to the notification image A and is equivalent to the notification image A. That is, the correction image C includes a second message CM, which is a character string "correction in progress", a second guide pattern CG that is a rectangular frame, and a second background image CB.

15 20 The second message CM, the second guide pattern CG, and the second background image CB may be stored in the memoryas individual images and combined together as the correction image C by the controller.

15 20 In the memory, the notification image A may be stored in the nonvolatile memory, and the correction image C may be stored in the volatile memory in a rewritable manner. In this case, the controllermay first copy the notification image A in the nonvolatile memory to the volatile memory and then rewrite the notification image A into the correction image C according to a correction value, described later.

The correction image C can also be said to be the notification image A or the notification image A that is corrected and changed.

The correction image C includes "correction in progress" of the second message CM, which is a character string notifying that the geometric correction processing is not finished. The second message CM is preferably located at the center of the correction image C.

1 1 The user can visually recognize the character string "correction in progress", which is the second message CM of the correction image C, and recognize that the projection deviceis in the state of "correction in progress" with respect to the projection image PG. The second guide pattern CG is preferably a rectangular frame including an area of a maximum range that can be projected by the projection device.

The gradation or the like of the second background image CB of the correction image C can be similar to that of the first background image AB of the notification image A described above.

In the second background image CB, the gradation becomes darker and the tint is blurred toward the center of the correction image C, and the gradation becomes lighter and the tint is blurred toward four corners CB1 to CB4. The four corners CB1 to CB4 of the second background image CB are a lower left corner CB1, an upper left corner CB2, an upper right corner CB3, and a lower right corner CB4. The four corners CB1 to CB4 are also the four corners of the correction image C and are also the four corners of the second guide pattern CG. The gradation may become lighter and the tint may be blurred toward the four sides of the second guide pattern CG representing a rectangle.

The gradation of the second background image CB is, for example, of a color such as red, green, or blue, and a single color is preferably used. The gradation may be of a color using gray tone including white. The second background image CB may be white without using gradation.

20 1 As will be described later, when the controllercorrects the correction image C, the correction image C is projected onto the projection surface SC while changing so as to reduce the keystone distortion. The user may visually recognize the correction image C that is automatically changed by the projection devicewithout being based on the user's own instruction or the like, and may feel that something is wrong.

1 Therefore, the projection devicechanges the correction image C so as to avoid causing the user to feel that something is wrong, as much as possible.

For example, a change at the four corners or on the four sides of the correction image C is more noticeable to the user. Therefore, in the second background image CB of the correction image C, the gradation is lighter and the tint is more blurred toward the four corners or the four sides, and the change is thus made less noticeable.

In this way, the brightness of the second background image CB of the correction image C increases continuously or in stages in the direction toward the periphery. In this case, the user is less likely to feel that something is wrong than when the second background image CB has an edge or the like in the vicinity of the periphery.

Even when the projection image PG and the correction image C are combined together, the gradation of the correction image C makes the change in the projection image PG less noticeable as well as in the correction image C. When the second background image CB is white, the second background image CB is less noticeable.

Such a second background image CB can achieve an effect of preventing the user from feeling that something is wrong.

The second message CM at the center of the correction image C has a clear contrast difference from the second background image CB having a dark gradation, and is easily visually recognized by the user. When the second background image CB is white, the second message CM may be black or colored.

The user can visually recognize the projection of the correction image C and grasp that the state of the processing of correcting the keystone distortion of the projection image PG is "correction in progress", and this is convenient.

With the second message CM and the second background image CB, the convenience for the user can be improved and an effect of preventing the user from feeling that something is wrong can be achieved.

20 24 10 The controllercauses the camerato pick up the correction image C projected on the projection surface SC, calculates the inclination of the housing, and corrects the correction image C such that the keystone distortion of the correction image C is reduced.

6 FIG. 5 FIG. Assuming that the correction image C is based on the notification image A, the following can be said. That is, it can be said that the second message CM, the second guide pattern CG, the second background image CB, and the like included in the correction image C illustrated inare the first message AM, the first guide pattern AG, the first background image AB, and the like included in the notification image A illustrated inthat are now being corrected or that are already corrected.

The correction of the keystone distortion as described above is referred to as so-called keystone correction. The keystone correction is an example of geometric correction. The geometric correction is also referred to as geometrical correction.

24 37 20 24 20 24 20 24 20 30 The keystone correction will be described in detail below. It is assumed that the positional relationship between the cameraand the projection lensis known due to a calibration in advance. The controllerspecifies a plurality of different positions in the second guide pattern CG of the correction image C picked up by the camera. The controllermeasures the distances to the specified plurality of positions by triangulation. The cameramay pick up an image different from the correction image C, for example, a dot pattern. In this case, the controllercauses the camerato pick up a dot pattern or the like instead of the correction image C, and measures the distance to the position of each dot by triangulation similarly to the above. The controllercauses the projectorto project the notification image A, the dot pattern, and the correction image C in this order.

20 10 1 20 10 15 The controllercan calculate the inclination of the housingof the projection devicewith respect to the projection surface SC, based on the measured distances. The controllercan calculate the correction value, based on the calculated inclination of the housing. The correction value is stored in the memory.

20 24 10 The controllermay detect a plurality of distances to the projection surface SC, using a TOF (time-of-flight) sensor instead of the camera, and calculate the inclination of the housing. In this case, the second guide pattern CG of the correction image C may be omitted.

20 10 20 When the controllerdetermines that the housingis not inclined, the controllermay end the correction processing. In this case, the second guide pattern CG of the picked-up correction image C represents the original rectangle.

20 15 20 5 FIG. 6 FIG. The controllerreads the correction value from the memoryand corrects the correction image C. For example, the controllercan correct the correction image C corresponding to the projection image PG distorted in a trapezoidal shape as shown insuch that the upper side and the lower side have the same length as shown in, using the correction value, and project the correction image C in the form of the original rectangle.

20 24 The controllercan pick up an image by the camerawhile projecting the correction image C, calculate the correction value, and give a feedback to correct the correction image C.

When the projection image PG and the correction image C are combined together, the projection image PG, too, can be corrected along with the correction image C.

20 1 When performing the keystone correction, the controllercan also correct the variation in the luminance based on the relative position between the projection deviceand the projection surface SC, and perform anti-aliasing processing, which is processing for smoothing the rough contour of the image.

20 37 The controllercan also control a lens drive motor (not shown) to adjust the focus, zoom, and the like of the projection lens.

20 15 107 When the correction is finished, the controllererases the correction image C from the memory(S), projects only the projection image PG, and ends the processing.

15 20 20 Specifically, when the projection image PG and the correction image C are combined together in the memory, the controllererases the correction image C. When only the correction image C is projected, the controllermay switch from the correction image C to the projection image PG. This switching is included in the above-described deletion of the correction image C.

1 30 10 30 27 10 20 As described above, the projection deviceaccording to the embodiment includes the projectorthat projects the projection image PG on the projection surface SC, the housingthat accommodates at least a part of the projector, the sensorthat detects a movement or stop of the housing, and one or a plurality of processors of the controller.

20 10 27 30 When the one or plurality of processors of the controllerdetermine that the housingis moving, based on the result of detection by the sensor, the one or plurality of processors cause the projectorto project the notification image A notifying that the processing of geometric correction on the projection image PG is not finished.

1 As a result, the user can visually recognize the notification image A of the projection deviceand easily grasp the state of the keystone distortion correction processing, and convenience is thus improved.

While the embodiments have been described in detail with reference to the drawings, the specific configurations are not limited to the embodiments, and may be changed, replaced, or deleted without departing from the spirit and scope of the disclosure.